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Journal articles on the topic '3d videography'
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Salgado, Moses D., Shane Curtiss, and Travis T. Tollefson. "Evaluating Symmetry and Facial Motion Using 3D Videography." Facial Plastic Surgery Clinics of North America 18, no. 2 (May 2010): 351–56. http://dx.doi.org/10.1016/j.fsc.2010.01.011.
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Flores, Francisco J., Silvia Sedano, Ana M. de Benito, and Juan C. Redondo. "Validity and reliability of a 3-axis accelerometer for measuring weightlifting movements." International Journal of Sports Science & Coaching 11, no. 6 (November 11, 2016): 872–79. http://dx.doi.org/10.1177/1747954116676114.
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The purpose of the current study was to assess the validity and reliability of measures obtained by a 3-axis commercial accelerometer during weightlifting movements in comparison with kinematic data derived from the 3D videography. Kinematic data from 3D videography were obtained from 11 track & field throwers performing 3 trials each one at different loads in power snatch, power clean and jerk from the rack. The results showed that the accelerometer measures were highly correlated with derived acceleration data from 3D videography data in the vertical plane (Z axis) taking up to the pull phase (including first pull, transition and second pull) for power snatch and power clean and up to the highest point of the bar path before the catch position (including dip, drive and split phases) for jerk from the rack. On the basis of these results, this device was proven to be valid and reliable on Z axis on the weightlifting movements studied. Thus, this system may be a useful and easy to handle tool to measure acceleration during real-time training sessions.
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de Margerie, E., M. Simonneau, J. P. Caudal, C. Houdelier, and S. Lumineau. "3D tracking of animals in the field using rotational stereo videography." Journal of Experimental Biology 218, no. 16 (June 8, 2015): 2496–504. http://dx.doi.org/10.1242/jeb.118422.
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Tran, Huy Hoang, Kiyoshi Matsumiya, Ken Masamune, Ichiro Sakuma, Takeyoshi Dohi, and Hongen Liao. "Interactive 3D Navigation System for Image-guided Surgery." International Journal of Virtual Reality 8, no. 1 (January 1, 2009): 9–16. http://dx.doi.org/10.20870/ijvr.2009.8.1.2708.
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This paper presents a novel surgery navigation system based on a three-dimensional (3D) imaging technique, integral videography (IV). In our system, the 3D structure of the object of interest is reconstructed using surface rendering and corresponding pixel distribution methods. We developed a high-speed algorithm that renders high-quality IV images from the surface model in real time and allows interactions like rotating and scaling to be done smoothly. Using the patient-image registration method, IV images can be displayed with the correct size and relative position with respect to the surgical instruments. Experiments were carried out with various anatomical models, and the results show that our system could be useful in many clinical situations such as orthopedic surgery and neurosurgery.
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Liao, Hongen, Susumu Nakajima, Makoto Iwahara, Etsuko Kobayashi, Ichiro Sakuma, Naoki Yahagi, and Takeyoshi Dohi. "Development of Real-Time 3D Navigation System for Intra-operative Information by Integral Videography." Journal of Japan Society of Computer Aided Surgery 2, no. 4 (2001): 245–52. http://dx.doi.org/10.5759/jscas1999.2.245.
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Liu, Qi, James G. Hay, and James G. Andrews. "Body Roll and Handpath in Freestyle Swimming: An Experimental Study." Journal of Applied Biomechanics 9, no. 3 (August 1993): 238–53. http://dx.doi.org/10.1123/jab.9.3.238.
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The purpose of this study was to determine the influence of (a) body roll, and (b) the motion of the arm relative to the trunk, on the medial-lateral component of the path followed by the hand during the pull phase in freestyle swimming. Ten male swimmers swam three trials of freestyle at a long-distance workout pace. Three-dimensional (3D) underwater videography was used to record the body roll angle-time history and the path followed by the hand during the pull phase. A mathematical model was used to characterize the motion of a swimmer's right upper limb in accord with 3D data from the videotape images, and to determine what the path of the hand would have been as a result of body roll alone. The contribution of body roll to the actual handpath was found to be nearly equal to the contribution of medial-lateral motions of the hand relative to the trunk.
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Boley, M., F. Abt, R. Weber, and T. Graf. "X-Ray and Optical Videography for 3D Measurement of Capillary and Melt Pool Geometry in Laser Welding." Physics Procedia 41 (2013): 488–95. http://dx.doi.org/10.1016/j.phpro.2013.03.105.
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Espinheira Gomes, Filipe, and Eric Ledbetter. "Canine and feline fundus photography and videography using a nonpatented 3D printed lens adapter for a smartphone." Veterinary Ophthalmology 22, no. 1 (May 11, 2018): 88–92. http://dx.doi.org/10.1111/vop.12577.
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Curran, Michael F., Kyle Summerfield, Emma-Jane Alexander, Shawn G. Lanning, Anna R. Schwyter, Melanie L. Torres, Scott Schell, Karen Vaughan, Timothy J. Robinson, and Douglas I. Smith. "Use of 3-Dimensional Videography as a Non-Lethal Way to Improve Visual Insect Sampling." Land 9, no. 10 (September 23, 2020): 340. http://dx.doi.org/10.3390/land9100340.
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Insects, the most diverse and abundant animal species on the planet, are critical in providing numerous ecosystem services which are significant to the United Nation’s Sustainable Development Goals (UN-SDGs). In addition to the UN-SDGs, the UN has declared the period 2021–2030 as the “Decade on Ecosystem Restoration.” Insects, because of the ecosystem services they provide, are critical indicators of restoration success. While the importance of insects in providing ecosystem services and their role in helping fulfil the UN-SDGs is recognized, traditional techniques to monitor insects may result in observer bias, high rates of type-I and type-II statistical error, and, perhaps most alarmingly, are often lethal. Since insects are critical in maintaining global food security, contribute to biological control and are a key food source for higher trophic levels, lethal sampling techniques which may harm insect populations are undesirable. In this study, we propose a method to visually sample insects which involves non-lethal 3-dimensional video cameras and virtual reality headsets. A total of eight observers viewed video captured insects visiting floral resources in a landscaped area on a university campus. While interobserver variability existed among individuals who partook in this study, the findings are similar to previous visual sampling studies. We demonstrate a combination of 3D video and virtual reality technology with a traditional insect count methodology, report monitoring results, and discuss benefits and future directions to improve insect sampling using these technologies. While improving quantitative monitoring techniques to study insects and other forms of life should always be strived for, it is a fitting time to introduce non-lethal sampling techniques as preservation and restoration of biodiversity are essential components of the UN-SDGs and the “Decade on Ecosystem Restoration”.
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Kwiatek, K., and R. Tokarczyk. "Photogrammetric Applications of Immersive Video Cameras." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences II-5 (May 28, 2014): 211–18. http://dx.doi.org/10.5194/isprsannals-ii-5-211-2014.
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The paper investigates immersive videography and its application in close-range photogrammetry. Immersive video involves the capture of a live-action scene that presents a 360° field of view. It is recorded simultaneously by multiple cameras or microlenses, where the principal point of each camera is offset from the rotating axis of the device. This issue causes problems when stitching together individual frames of video separated from particular cameras, however there are ways to overcome it and applying immersive cameras in photogrammetry provides a new potential. The paper presents two applications of immersive video in photogrammetry. At first, the creation of a low-cost mobile mapping system based on Ladybug®3 and GPS device is discussed. The amount of panoramas is much too high for photogrammetric purposes as the base line between spherical panoramas is around 1 metre. More than 92 000 panoramas were recorded in one Polish region of Czarny Dunajec and the measurements from panoramas enable the user to measure the area of outdoors (adverting structures) and billboards. A new law is being created in order to limit the number of illegal advertising structures in the Polish landscape and immersive video recorded in a short period of time is a candidate for economical and flexible measurements off-site. The second approach is a generation of 3d video-based reconstructions of heritage sites based on immersive video (structure from immersive video). A mobile camera mounted on a tripod dolly was used to record the interior scene and immersive video, separated into thousands of still panoramas, was converted from video into 3d objects using Agisoft Photoscan Professional. The findings from these experiments demonstrated that immersive photogrammetry seems to be a flexible and prompt method of 3d modelling and provides promising features for mobile mapping systems.
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Patel, Shiv H., Wonjun Yim, Anupam K. Garg, Sahil H. Shah, Jesse V. Jokerst, and Daniel L. Chao. "Assessing the Physiological Relevance of Cough Simulators for Respiratory Droplet Dispersion." Journal of Clinical Medicine 9, no. 9 (September 17, 2020): 3002. http://dx.doi.org/10.3390/jcm9093002.
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Various breathing and cough simulators have been used to model respiratory droplet dispersion and viral droplets, in particular for SARS-CoV-2 modeling. However, limited data are available comparing these cough simulations to physiological breathing and coughing. In this study, three different cough simulators (Teleflex Mucosal Atomization Device Nasal (MAD Nasal), a spray gun, and GloGermTM MIST) that have been used in the literature were studied to assess their physiologic relevance. Droplet size, velocity, dispersion, and force generated by the simulators were measured. Droplet size was measured with scanning electron microscopy (SEM). Slow-motion videography was used to 3D reconstruct and measure the velocity of each simulated cough. A force-sensitive resistor was used to measure the force of each simulated cough. The average size of droplets from each cough simulator was 176 to 220 µm. MAD Nasal, the spray gun, and GloGermTM MIST traveled 0.38 m, 0.89 m, and 1.62 m respectively. The average velocities for the MAD Nasal, spray gun, and GloGermTM MIST were 1.57 m/s, 2.60 m/s, and 9.27 m/s respectively, and all yielded a force of <0.5 Newtons. GloGermTM MIST and the spray gun most closely resemble physiological coughs and breathing respectively. In conclusion, none of the simulators tested accurately modeled all physiologic characteristics (droplet size, 3-D dispersion velocity, and force) of a cough, while there were various strengths and weaknesses of each method. One should take this into account when performing simulations with these devices.
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York, Carly A., Ian K. Bartol, Paul S. Krueger, and Joseph T. Thompson. "Squids use multiple escape jet patterns throughout ontogeny." Biology Open 9, no. 11 (September 24, 2020): bio054585. http://dx.doi.org/10.1242/bio.054585.
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ABSTRACTThroughout their lives, squids are both predators and prey for a multitude of animals, many of which are at the top of ocean food webs, making them an integral component of the trophic structure of marine ecosystems. The escape jet, which is produced by the rapid expulsion of water from the mantle cavity through a funnel, is central to a cephalopod's ability to avoid predation throughout its life. Although squid undergo morphological and behavioral changes and experience remarkably different Reynolds number regimes throughout their development, little is known about the dynamics and propulsive efficiency of escape jets throughout ontogeny. We examine the hydrodynamics and kinematics of escape jets in squid throughout ontogeny using 2D/3D velocimetry and high-speed videography. All life stages of squid produced two escape jet patterns: (1) ‘escape jet I’ characterized by short rapid pulses resulting in vortex ring formation and (2) ‘escape jet II’ characterized by long high-volume jets, often with a leading-edge vortex ring. Paralarvae exhibited higher propulsive efficiency than adult squid during escape jet ejection, and propulsive efficiency was higher for escape jet I than escape jet II in juveniles and adults. These results indicate that although squid undergo major ecological transitions and morphology changes from paralarvae to adults, all life stages demonstrate flexibility in escape jet responses and produce escape jets of surprisingly high propulsive efficiency.This article has an associated First Person interview with the first author of the paper.
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Wood, Hannah M. "Morphology and performance of the ‘trap-jaw’ cheliceral strikes in spiders (Araneae, Mecysmaucheniidae)." Journal of Experimental Biology 223, no. 14 (June 19, 2020): jeb219899. http://dx.doi.org/10.1242/jeb.219899.
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ABSTRACTMecysmaucheniidae spiders have evolved ultra-fast cheliceral strikes 4 times independently. The mechanism for producing these high-speed strikes is likely due to a latch/spring system that allows for stored energy to be rapidly released. This study examined two different sister lineages: Zearchaea has ultra-fast cheliceral strikes and Aotearoa, based on external morphology of the clypeus, is hypothesized to have slower strikes. Using high-speed videography, I first gathered kinematic data on each taxon. Then, using histology and data from micro-computed tomography scanning, I examined internal cheliceral muscle morphology to test whether shifts in muscle anatomy correspond to performance differences in cheliceral strike. Results from high-speed video analysis revealed that Zearchaea achieves peak angular velocities of 25.0×103±4.8×103 rad s−1 (mean±s.d.) in durations of 0.0843±0.017 ms. The fastest recorded strike had a peak angular and linear velocity of 30.8×103 rad s−1 and 18.2 m s−1, respectively. The slower striking sister species, Aotearoa magna, was three orders of magnitude slower in velocity and longer in duration. Histology revealed sarcomere length differences, with some muscles optimized for force, and other muscles for speed. 3D printed models revealed structural differences that explain how the chelicerae hinge open and close. Combining all of this evidence, I put forth a hypothesis for the ultra-fast trap-jaw mechanism. This research documents the morphological shifts that accompany ultra-fast movements that result in increased rotation in joints and increased muscle specialization.
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Hass, Chris J., Elizabeth A. Schick, John W. Chow, Mark D. Tillman, Denis Brunt, and James H. Cauraugh. "Lower Extremity Biomechanics Differ in Prepubescent and Postpubescent Female Athletes during Stride Jump Landings." Journal of Applied Biomechanics 19, no. 2 (May 2003): 139–52. http://dx.doi.org/10.1123/jab.19.2.139.
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Epidemiological evidence suggests the incidence of injury in female athletes is greater after the onset of puberty and that landing from a jump is a common mechanism of knee injury. This investigation compared lower extremity joint kinematics and joint resultant forces and moments during three types of stride jump (stride jump followed by a static landing; a ballistic vertical jump; and a ballistic lateral jump) between pre- and postpubescent recreational athletes to provide some insight into the increased incidence of injury. Sixteen recreationally active postpubescent women (ages 18–25 years) and 16 recreationally active prepubescent girls (ages 8–11 years) participated in this study. High speed 3D videography and force plate data were used to record each jumper’s performance of the stride jumps, and an inverse dynamic procedure was used to estimate lower extremity joint resultant forces and moments and power. These dependent variables were submitted to a 2 × 3 (Maturation Level × Landing Sequence) MANOVA with repeated measures on the last factor. The findings indicated that postpubescents landed with the knee more extended (4.4°) and had greater extension moments (approximately 30% greater hip and knee extension moments) and powers (40% greater knee power). Further, the post-pubescent athletes had greater knee anterior/posterior forces as well as medio-lateral resultant forces. The differences found between the two groups suggest there may be anatomical and physiological changes with puberty that lead to differences in strength or neuromuscular control which influence the dynamic restraint system in these recreational athletes. A combination of these factors likely plays a role in the increased risk of injury in postpubescent females.
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M, Mayma Nathasha, Sushil Chakravarthi N.C., Dilip Srinivasan, Priya Kalidass, Davis D., Shreya Kishore, and Suvetha S. "Orthodontics in the Era of Digital Innovation – A Review." Journal of Evolution of Medical and Dental Sciences 10, no. 28 (July 12, 2021): 2114–21. http://dx.doi.org/10.14260/jemds/2021/432.
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The field of orthodontics in its new era is venturing ahead to more up-to-date technological point of view. Digital technology has a significant effect on our lives ever since the modernization of mobile phones. The advances in technology have remodelled the diagnosis and treatment plan in the field of medicine. Digital workflows are currently increasing in the orthodontic practice and has touched every aspect of orthodontics – with transformations in the documentation, study casts, analysis of a dental malocclusion, smile designing, treatment planning and for fabrication of orthodontic appliances. Three - dimensional imaging of the dentition, skeletal components and the face allows for treatment planning in three dimension and use of computer aided design (CAD) and computer aided manufacturing (CAM) for customization of orthodontic appliances. Software integration of digital models, 3D facial imaging and cone-beam computed tomography (CBCT) makes it possible to simulate the treatment plan and to attain a good communication with the patients. Recent advancement in digital videography has allowed the clinicians to capture patient’s speech, oral and pharyngeal function, and smile at the same time. Effective and optimal tooth movement required for the patient can also be monitored with the digitalization. Moreover, this digital platform has created the advantage of accessing the patient’s information from any location with the help of cloud based computing storage systems. These advancements have improved the efficiency, accuracy, consistency, and predictability of the treatment outcomes and have also led to progress in educational component and communication. The digitalization is bringing about a revolutionary change in the field of diagnosis and treatment planning, posing a challenge to clinical efficiency and knowledge. KEY WORDS Digital Orthodontics, Digital Workflow, Digital Dental Models, Digital Radiography, CAD CAM, Orthodontics, Review
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Vollin, Marina F., and Timothy E. Higham. "Tail Autotomy Alters Prey Capture Performance and Kinematics, but not Success, in Banded Geckos." Integrative and Comparative Biology 61, no. 2 (May 14, 2021): 538–49. http://dx.doi.org/10.1093/icb/icab076.
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Abstract Tails are versatile structures with diverse forms and functions across vertebrates. They are involved in almost all behaviors critical to survival including locomotion, feeding, and predator avoidance. Although the tail’s role in locomotion and stability has been widely studied, its role in prey capture is relatively unknown. Lizards are an ideal system to examine the tail’s impact on prey capture as most are capable of autotomizing, or dropping, their tail in response to predation and intraspecific competition. Tail autotomy can lower reproduction, decrease locomotor performance, impart instability during jumping, and decrease social status. Desert banded geckos (Coleonyx variegatus) frequently capture evasive prey in nature and appear to use their tail during strikes. However, it is unclear if these tail movements are important for the strike itself, or if they simply draw attention to that part of the body. We used high-speed 3D videography to quantify prey capture performance and kinematics of C. variegatus striking at crickets before and after total caudal autotomy. Trials were conducted within 2 h of autotomy and then repeatedly over a 2-week period. Overall, prey capture success was unaffected by caudal autotomy. However, maximum strike velocity decreased significantly after autotomy, highlighting the importance of the tail during prey capture. Strike kinematics were altered after autotomy in several ways, including geckos adopting a more sprawled posture. Maximum pectoral girdle and mid-back height were significantly lower during post-autotomy strikes, whereas maximum pelvic girdle height was unaffected. However, individual variation was considerable. This downward pitching of the body after tail loss suggests that the tail is necessary for counterbalancing the anterior portion of the body and resisting the rotational inertia incurred after pushing off with the hindlimbs. Utilizing autotomy to test tail function in prey capture can provide valuable insight into how the tail is used in terrestrial predation across a wide variety of species and ecological niches.
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Englander, Zoë A., Hattie C. Cutcliffe, Gangadhar M. Utturkar, William E. Garrett, Charles E. Spritzer, and Louis E. DeFrate. "A Comparison of Knee Abduction Angles Measured by a 3D Anatomic Coordinate System Versus Videographic Analysis: Implications for Anterior Cruciate Ligament Injury." Orthopaedic Journal of Sports Medicine 7, no. 1 (January 1, 2019): 232596711881983. http://dx.doi.org/10.1177/2325967118819831.
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Background: Knee positions involved in noncontact anterior cruciate ligament (ACL) injury have been studied via analysis of injury videos. Positions of high ACL strain have been identified in vivo. These methods have supported different hypotheses regarding the role of knee abduction in ACL injury. Purpose/Hypothesis: The purpose of this study was to compare knee abduction angles measured by 2 methods: using a 3-dimensional (3D) coordinate system based on anatomic features of the bones versus simulated 2-dimensional (2D) videographic analysis. We hypothesized that knee abduction angles measured in a 2D videographic analysis would differ from those measured from 3D bone anatomic features and that videographic knee abduction angles would depend on flexion angle and on the position of the camera relative to the patient. Study Design: Descriptive laboratory study. Methods: Models of the femur and tibia were created from magnetic resonance images of 8 healthy male participants. The models were positioned to match biplanar fluoroscopic images obtained as participants posed in lunges of varying flexion angles (FLAs). Knee abduction angle was calculated from the positioned models in 2 ways: (1) varus-valgus angle (VVA), defined as the angle between the long axis of the tibia and the femoral transepicondylar axis by use of a 3D anatomic coordinate system; and (2) coronal plane angle (CPA), defined as the angle between the long axis of the tibia and the long axis of the femur projected onto the tibial coronal plane to simulate a 2D videographic analysis. We then simulated how changing the position of the camera relative to the participant would affect knee abduction angles. Results: During flexion, when CPA was calculated from a purely anterior or posterior view of the joint—an ideal scenario for measuring knee abduction from 2D videographic analysis—CPA was significantly different from VVA ( P < .0001). CPA also varied substantially with the position of the camera relative to the participant. Conclusion: How closely CPA (derived from 2D videographic analysis) relates to VVA (derived from a 3D anatomic coordinate system) depends on FLA and camera orientation. Clinical Relevance: This study provides a novel comparison of knee abduction angles measured from 2D videographic analysis and those measured within a 3D anatomic coordinate system. Consideration of these findings is important when interpreting 2D videographic data regarding knee abduction angle in ACL injury.
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Wahlang, Imayanmosha, Arnab Kumar Maji, Goutam Saha, Prasun Chakrabarti, Michal Jasinski, Zbigniew Leonowicz, and Elzbieta Jasinska. "Deep Learning Methods for Classification of Certain Abnormalities in Echocardiography." Electronics 10, no. 4 (February 20, 2021): 495. http://dx.doi.org/10.3390/electronics10040495.
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This article experiments with deep learning methodologies in echocardiogram (echo), a promising and vigorously researched technique in the preponderance field. This paper involves two different kinds of classification in the echo. Firstly, classification into normal (absence of abnormalities) or abnormal (presence of abnormalities) has been done, using 2D echo images, 3D Doppler images, and videographic images. Secondly, based on different types of regurgitation, namely, Mitral Regurgitation (MR), Aortic Regurgitation (AR), Tricuspid Regurgitation (TR), and a combination of the three types of regurgitation are classified using videographic echo images. Two deep-learning methodologies are used for these purposes, a Recurrent Neural Network (RNN) based methodology (Long Short Term Memory (LSTM)) and an Autoencoder based methodology (Variational AutoEncoder (VAE)). The use of videographic images distinguished this work from the existing work using SVM (Support Vector Machine) and also application of deep-learning methodologies is the first of many in this particular field. It was found that deep-learning methodologies perform better than SVM methodology in normal or abnormal classification. Overall, VAE performs better in 2D and 3D Doppler images (static images) while LSTM performs better in the case of videographic images.
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Scott, Catherine B., Christopher H. Roosevelt, Gary R. Nobles, and Christina Luke. "Born-Digital Logistics: Impacts of 3D Recording on Archaeological Workflow, Training, and Interpretation." Open Archaeology 7, no. 1 (January 1, 2021): 574–88. http://dx.doi.org/10.1515/opar-2020-0150.
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Abstract Digital technologies have been at the heart of fieldwork at the Kaymakçı Archaeological Project (KAP) since its beginning in 2014. All data on this excavation are born-digital, from textual, photographic, and videographic descriptions of contexts and objects in a database and excavation journals to 2D plans and profiles as well as 3D volumetric recording of contexts. The integration of structure from motion (SfM) modeling and its various products has had an especially strong impact on how project participants interact with the archaeological record during and after excavation. While this technology opens up many new possibilities for data recording, analysis, and presentation, it can also present challenges when the requirements of the recording system come into conflict with an archaeologist’s training and experience. Here, we consider the benefits and costs of KAP’s volumetric recording system. We explore the ways that recording protocols for image-based modeling change how archaeologists see and manage excavation areas and how the products of this recording system are revolutionizing our interaction with the (digital) archaeological record. We also share some preliminary plans for how we intend to expand this work in the future.
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GLOEKLER, M. D., T. P. BALLESTERO, E. V. DAVE, I. P. GAUDREAU, C. B. R. WATKINS, and N. E. KINNER. "MOVEMENT AND EROSION OF ALBERTA BITUMEN ALONG THE BOTTTOM AS A FUNCTION OF TEMPERATURE, WATER VELOCITY AND SALINITY." International Oil Spill Conference Proceedings 2017, no. 1 (May 1, 2017): 2306–26. http://dx.doi.org/10.7901/2169-3358-2017.1.2306.
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Abstract While many trajectory models exist to predict the movement of oil floating in or on water, few are designed to address heavy oil on the bottom of water bodies. In addition, remobilization (erosion) of the material into the water column is also difficult to predict. While properties such as adhesion, viscosity and density of oil may be readily measured, the critical shear stress (CSS) and the effect of (current) velocity, salinity, and temperature are virtually unknown for most heavy oils. The Coastal Response Research Center (CRRC) has a 4,000 L annular flume, with a water depth of 0.43 m. An inner rectangular flume (1.2 m length, 0.2m width, 0.9 m height), placed inside the annular flume, was preceded by two flow straighteners to reduced turbulence and produce a uniform, one dimensional flow field. The current is generated by an electric thrust motor and measured in 3D by a Nortek AS (Norway) Vectrino II Profiling Velocimeter. A 20g circle of Alberta bitumen (API ~ 10°) was placed on a laminated grid (1cm2 square pattern) at the bottom of the straight flume. A total of 2.3m3 of water was then gradually added to the flume. The electric motor was started and the profiler began collecting data. Two cameras, placed along the side and above the oil, collected video of the erosions and length/width changes of the oil. Conditions were held steady for one hour once the desired current velocity was achieved. Temperatures, current velocity (X, Y, Z), and digital videographic data were collected during each run. Erosions and percent lengthening of the oil was monitored as a function of water temperature, salinity and velocity. The turbulent kinetic energy (TKE) method was used to calculate the bed shear stress (BSS). In addition to the expected impact of higher temperature on the movement along the bed and erosion into the water column, the viscoelastic and shear-thinning properties of the bitumen played a role in its behavior (lowering of viscosity at higher BSS slowing erosions and movement) and must be considered when predicting its behavior during a spill.
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Lee, Mark, Hazel T. Rivera-Rosario, Matthew H. Kim, Gregory P. Bewley, Jane Wang, Zellman Warhaft, Bradley Stylman, et al. "Development and validation of a patient face-mounted, negative-pressure antechamber for reducing exposure of healthcare workers to aerosolized particles during endonasal surgery." Journal of Neurosurgery, May 2021, 1–8. http://dx.doi.org/10.3171/2020.10.jns202745.
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OBJECTIVE The authors developed a negative-pressure, patient face-mounted antechamber and tested its efficacy as a tool for sequestering aerated particles and improving the safety of endonasal surgical procedures. METHODS Antechamber prototyping was performed with 3D printing and silicone-elastomer molding. The lowest vacuum settings needed to meet specifications for class I biosafety cabinets (flow rate ≥ 0.38 m/sec) were determined using an anemometer. A cross-validation approach with two different techniques, optical particle sizing and high-speed videography/shadowgraphy, was used to identify the minimum pressures required to sequester aerosolized materials. At the minimum vacuum settings identified, physical parameters were quantified, including flow rate, antechamber pressure, and time to clearance. RESULTS The minimum tube pressures needed to meet specifications for class I biosafety cabinets were −1.0 and −14.5 mm Hg for the surgical chambers with (“closed face”) and without (“open face”) the silicone diaphragm covering the operative port, respectively. Optical particle sizing did not detect aerosol generation from surgical drilling at these vacuum settings; however, videography estimated higher thresholds required to contain aerosols, at −6 and −35 mm Hg. Simulation of surgical movement disrupted aerosol containment visualized by shadowgraphy in the open-faced but not the closed-faced version of the mask; however, the closed-face version of the mask required increased negative pressure (−15 mm Hg) to contain aerosols during surgical simulation. CONCLUSIONS Portable, negative-pressure surgical compartments can contain aerosols from surgical drilling with pressures attainable by standard hospital and clinic vacuums. Future studies are needed to carefully consider the reliability of different techniques for detecting aerosols.
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Abdulhafez, Moataz, Jaegeun Lee, and Mostafa Bedewy. "In Situ Measurement of Carbon Nanotube Growth Kinetics in a Rapid Thermal Chemical Vapor Deposition Reactor With Multizone Infrared Heating." Journal of Micro and Nano-Manufacturing 8, no. 1 (February 13, 2020). http://dx.doi.org/10.1115/1.4046033.
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Abstract Understanding and controlling the growth of vertically aligned carbon nanotube (VACNT) forests by chemical vapor deposition (CVD) is essential for unlocking their potential as candidate materials for next generation energy and mass transport devices. These advances in CNT manufacturing require developing in situ characterization techniques capable of interrogating how CNTs grow, interact, and self-assemble. Here we present a technique for real-time monitoring of VACNT forest height kinetics applied to a unique custom designed rapid thermal processing (RTP) reactor for CVD of VACNTs. While the integration of multiple infrared heating lamps enables creating designed spatiotemporal temperature profiles inside the reactor, they pose challenges for in situ measurements. Hence, our approach relies on contrast-adjusted videography and image processing, combined with calibration using 3D optical microscopy with large depth-of-field. Our work enables reliably measuring VACNT growth rates and catalytic lifetimes, which are not possible to measure using ex situ methods.
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Elsisy, Moataz, Evan Poska, Moataz Abdulhafez, and Mostafa Bedewy. "Current-Dependent Dynamics of Bidirectional Self-Folding for Multi-Layer Polymers Using Local Resistive Heating." Journal of Engineering Materials and Technology 143, no. 3 (February 3, 2021). http://dx.doi.org/10.1115/1.4049588.
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Abstract The purpose of this paper is to characterize the dynamics and direction of self-folding of pre-strained polystyrene (PSPS) and non-pre-strained styrene (NPS), which results from local shrinkage using a new process of directed self-folding of polymer sheets based on a resistively heated ribbon that is in contact with the sheets. A temperature gradient across the thickness of this shape memory polymer (SMP) sheet induces folding along the line of contact with the heating ribbon. Varying the electric current changes the degree of folding and the extent of local material flow. This method can be used to create practical three-dimensional (3D) structures. Sheets of PSPS and NPS were cut to 10 × 20 mm samples, and their folding angles were plotted with respect to time, as obtained from in situ videography. In addition, the use of polyimide tape (Kapton) was investigated for controlling the direction of self-folding. Results show that folding happens on the opposite side of the sample with respect to the tape, regardless of which side the heating ribbon is on, or whether gravity is opposing the folding direction. The results are quantitatively explained using a viscoelastic finite element model capable of describing bidirectional folds arising from the interplay between viscoelastic relaxation and strain mismatch between polystyrene and polyimide. Given the tunability of fold times and the extent of local material flow, resistive-heat-assisted folding is a promising approach for manufacturing complex 3D lightweight structures by origami engineering.
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McInnes, Kurt A., Zelalem A. Abebe, Thomas Whyte, Asma Bashir, Carlos Barron, Cheryl L. Wellington, and Peter A. Cripton. "An Automated Kinematic Measurement System for Sagittal Plane Murine Head Impacts." Journal of Biomechanical Engineering 142, no. 8 (July 6, 2020). http://dx.doi.org/10.1115/1.4046202.
Full textAbstract:
Abstract Mild traumatic brain injuries are typically caused by nonpenetrating head impacts that accelerate the skull and result in deformation of the brain within the skull. The shear and compressive strains caused by these deformations damage neural and vascular structures and impair their function. Accurate head acceleration measurements are necessary to define the nature of the insult to the brain. A novel murine head tracking system was developed to improve the accuracy and efficiency of kinematic measurements obtained with high-speed videography. A three-dimensional (3D)-printed marker carrier was designed for rigid fixation to the upper jaw and incisors with an elastic strap around the snout. The system was evaluated by impacting cadaveric mice with the closed head impact model of engineered rotational acceleration (CHIMERA) system using an energy of 0.7 J (5.29 m/s). We compared the performance of the head-marker system to the previously used skin-tracking method and documented significant improvements in measurement repeatability (aggregate coefficient of variation (CV) within raters from 15.8 to 1.5 and between raters from 15.5 to 1.5), agreement (aggregate percentage error from 24.9 to 8.7), and temporal response (aggregate temporal curve agreement from 0.668 to 0.941). Additionally, the new system allows for automated software tracking, which dramatically decreases the analysis time required (74% reduction). This novel head tracking system for mice offers an efficient, reliable, and real-time method to measure head kinematics during high-speed impacts using CHIMERA or other rodent or small mammal head impact models.
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Camacaro, Marelvy, Alberto Colina, and Mihai Zissu. "Análisis de las variables cinemáticas en la técnica del pateo en el fútbol a partir de criterios de eficiencia biomecánicos." SPORT TK-Revista EuroAmericana de Ciencias del Deporte 10, no. 2 (August 10, 2021). http://dx.doi.org/10.6018/sportk.429211.
Full textAbstract:
La presente investigación se realizó con el objetivo de analizar las variables cinemáticas que se manifiestan en la técnica del pateo en el fútbol a partir de criterios de eficiencia biomecánicos. Fue una investigación de nivel descriptivo, con un diseño de campo, basado en un estudio de caso con una atleta de 15 años. Se utilizó el método videográfico tridimensional (3D) con los enfoques: cuantitativo (programa “Human v 5.0”) y cualitativo (escala Likert). Se cuantificaron las variables cinemáticas mediante pre y pos test. Se establecieron criterios de eficiencia para optimizar variables biomecánicas en las fases: Preparatoria y Pateo. Así, se orientó el entrenamiento de la adolescente en función de fortalezas y debilidades identificadas desde la perspectiva biomecánica, lo que permitió optimizar la técnica de los miembros inferiores, dominante y no dominante. Entre otros resultados, destacó el aumento de sincronización y consecuente mejoría del patrón temporal de movimiento lo que facilitó la coordinación de impulso parcial, y por ende la transferencia de energía del cuerpo hacia el balón, incidiendo positivamente en la velocidad resultante, trayectoria y precisión del balón con lo cual aumentó la frecuencia del gol, hecho que incidió en el rendimiento y perfil de la joven, destacándose en la posición lateral con un manejo eficiente del balón por ambos perfiles. The present investigation was carried out with the objective of analyzing the kinematic variables that are manifested in the kicking technique in soccer based on biomechanical efficiency criteria. It was a descriptive level investigation, with a field design, based on a case study with a 15-year-old athlete. The three-dimensional (3D) videographic method was used with the approaches: quantitative (“Human v 5.0” program) and qualitative (Likert scale). Kinematic variables were quantified by pre and posttest. Efficiency criteria were established to optimize biomechanical variables in the phases: Preparatory and Kicking. Thus, the adolescent's training was oriented according to the strengths and weaknesses identified from the biomechanical perspective, which allowed optimizing the technique of the dominant and non-dominant lower limbs. Among other results, the increase in synchronization and consequent improvement in the temporal pattern of movement stood out, which facilitated the coordination of partial impulse, and therefore the transfer of energy from the body to the ball, positively influencing the resulting speed, trajectory and precision of the ball which increased the frequency of the goal, a fact that affected the performance and profile of the young woman, standing out in the lateral position with an efficient handling of the ball by both profile.